Self-propelled rifle grenade capable of being launched by bullet impact



Nov. 25, 1969 L. BIRKIGT SELF-PROPELLED RIFLE GRENADE CAPABLE OF BEINGLAUNCHED BY BULLET IMPACT 2 Sheets-Sheet 1 Filed Aug. 31, 1967 Nov. 25,1969 1.. BIRKIGT 3,479,956

SEbF-PROPELLED RIFLE GRENADE CAPABLE OF BEING LAUNCHED BY BULLET IMPACTFiled Aug. 31, 1967 2 Sheets-Sheet 2 United States Patent 3,479,956SELF-PROPELLED RIFLE GRENADE CAPABLE OF BEING LAUNCHED BY BULLET IMPACTLouis Birkigt, Pregny-Geneva, Switzerland, assignor to BrevetsAero-Mecaniques S.A., Geneva, Switzerland Filed Aug. 31, 1967, Ser. No.664,667 Claims priority, application Luxembourg, Sept. 14, 1966, 51,960;Oct. 13, 1966, 52,164 Int. Cl. F42b 11/42 US. Cl. 10265.2 1 ClaimABSTRACT OF THE DISCLOSURE The invention relates to a grenade to belaunched by means of a bullet from a rifle on the end of the barrel ofwhich a tubular tail of the grenade is fitted, said bullet striking anaxial obstacle carried by the grenade. The grenade further comprises anauxiliary propelling charge delivering powder gases through annularnozzle means opening toward the rear, and igniting means extending fromthe axial obstacle to said auxiliary propelling charge.

The present invention relates to grenades to be launched by means of afirearm (for instance a rifle), such a grenade being fitted, inlaunching position, on the end of the rifle barrel and launching properbeing performed by firing a bullet, which is generally, but notnecessarily, of the type normally used with this rifle.

The object of the present invention is to provide a grenade of this kindwhich is better adapted to meet the requirements of practice than thoseknown up to now and in particular a grenade comprising auxiliarypropelling means which improve the performance obtained.

Such a grenade comprises a supporting sleeve located at the rear of thegrenade and adapted to fit 0n the outer surface of the front end of thelaunching gun barrel, said sleeve carrying advantageously in the frontpart thereof, an axial obstacle capable of collecting and transmittingto the grenade the impulse produced by the impact of a bullet fired bythe rifle.

According to the present invention, the grenade further comprises anauxiliary propulsion charge located coaxially on the outside of saidsupporting sleeve, preferably at the level of said axial obstacle, andigniting means extending from said axial obstacle to said auxiliarypropulsion charge, said igniting means being adapted to be operated bythe impact of the launching bullet on said axial obstacle.

Preferred embodiments of the present invention will be hereinafterdescribed with reference to the appended drawings given merely by way ofexample and in which,

FIG. 1 is a diagrammatic elevational view, with parts in section, of agrenade according to this invention;

FIG. 2 is a perspective view illustrating a modification;

FIG. 3 is another perspective view illustrating another modification.

The grenade according to this invention, an embodiment of which is shownby FIG. 1, includes an intermediate body 1 extending frontwardly to forma war-head 2 and provided, rearwardly thereof, with a supporting sleeve3 adapted to fit on the front end of the launching rifle barrel (whichmay carry an accessory such as a muzzle brake or a flame shield). Sleeve3 may carry fins 4.

This grenade is provided with an axial obstacle 5, for instance ofsteel, for collecting and transmitting to the grenade the impulseresulting from the impact on said obstacle of a launching bullet firedfrom the rifle. The Ohstacle 5 is rigid with, that is, immovable withrespect to the sleeve. Said obstacle consists for instance of afrustoconical piece housed in the front part of sleeve 3. The

3,479,956 Patented Nov. 25, 1969 ice large base of said frusto-conicalpiece is at the rear and the small base, provided with a fixation flange5a, at the front.

NOW, according to the main feature of the present invention, the grenadefurther comprises the following elements:

Auxiliary propelling means 6 (booster means) capable of improving theperformance of the grenade and disposed on the outside of sleeve 3 andcoaxially therewith, preferably, as shown, in the front portion of saidsleeve, between the front end thereof and the center of gravity G of thegrenade, and

Igniting means extending from axial obstacle 5 to auxiliary propellingmeans 6, said igniting means being adapted to be operated by the impactof the launching bullet on axial obstacle 5.

Auxiliary propelling means 6 are advantageously arranged to include apropellent charge symmetrically disposed about the axis of the grenade,the gases from said charge flowing out through at least one nozzle 6a.

Auxiliary propelling means 6 may include:

Either an annular propellent charge made of a single block and adaptedto feed combustion gases either to a single annular nozzle or to severalcircular nozzles disposed in a circular row at equal intervals from oneanother,

Or a propellent charge made of several similar elements disposed in acircular or closed polygonal row at equal intervals from One another,which elements may feed combustion gases either to a single annularnozzle or to several circular nozzles disposed in circular row at equalintervals from one another. In particular every propellent element mayfeed its combustion gases to a corresponding nozzle.

On the other hand, when the auxiliary propelling means 6 include severalnozzles 6a disposed in circular row, it is advantageous, according toanother feature of the present invention illustrated by FIG. 2, toarrange at least some of these nozzles 6a (in particular by suitablyinclining the nozzle axis, at least in the downstream portion thereof)in such manner that the velocity V of the propelling streams issuingfrom the nozzles has a tangential component Vt extending in the samerelative direction for all of said nozzles. In this case said componentsVt impart to the grenade, as soon as the auxiliary propelling charge isignited, a stabilizing gyratory movement about the grenade axis.

In both cases, i.e., either when auxiliary propelling charge 6 includesseveral circular nozzles disposed in a circular row or when saidauxiliary propelling charge includes a single annular nozzle, it will beof advantage, according to another feature of the invention, to arrangesaid annular nozzle or said circular row of nozzles in such manner thatthe total propelling stream issuing from auxiliary propelling means 6forms a frusto-conical sheet (either continuous or discontinuous)converging, at least approximately, toward a point P located at the rearof, and preferably close to, the center of gravity G of the grenade.

This means that the nozzle or nozzles 6a are arranged so that, at anypoint of the outlet section of the propelling stream forming afrusto-conical sheet, the discharge velocity V has a radial componentVr.

According to the preferred embodiment of the invention illustrated bythe drawings, according to which auxiliary propelling means 6 isdisposed at the rear of the center of gravity G of the grenade, thearrangement of the nozzle or nozzles 6a will be such that the radialcomponent Vr is directed outwardly and has an intensity such that theconvergence point P is located slightly at the rear of the center ofgravity G.

This last mentioned feature of the invention considerably reduces therisks of an increased dispersion in the case where the output of somenozzles (or of some sectors of an annular nozzle) would be accidentallygreater than the output of other nozzles or nozzle sectors.

This lack of symmetry of the outputs involves a bending in a givendirection of the trajectory of the grenade but owing to the fact thatthe point of convergence P is located at the rear of the center ofgravity G, the grenade then pivots about said center of gravity in adirection opposed to that in which the trajectory has been bent, that isto say, in a direction moving its axis toward the direction of thefiring axis. It follows that, as soon as the combustion of auxiliarypropelling means 6 is finished, it will suflice to obtain a slightswinging of the grenade to return it in the direction of the firingaxis, this slight swinging being quickly ensured by the tail unit 4 ofthe grenade.

It will be possible to combine the benefits of the above mentionedsecond and third features. This result may be obtained, for instance,

Either by arranging the nozzles of a circular row of nozzles alternatelyaccording to said second and to said third feature,

Or by providing two concentric annular rows of nozzles disposedrespectively according to the second feature and to the third feature,

Or again, by arranging similarly all the nozzles of an annular row insuch manner that the output velocities have both a tangential componentVt and a radial component Vr, which corresponds to substituting forconvergence point P a circumference having its center at said point andlocated in a transverse plane, the respective lines of the vectorsrepresentative of the output velocities V passing through differentpoints of said circumference.

Concerning now the igniting means to be operated by the firing of thelaunching bullet, they may be made as follows:

An ignition relay is provided between auxiliary propelling device 6 anda primer or the like 7 carried by axial obstacle and preferably locatednear the front of said axial obstacle.

This ignition relay may advantageously include a transmission charge 8consisting of an incendiary composition located immediately at the frontof primer 7, said transmission charge 8 being in communication throughat least one radial conduit 9 (and preferably several such conduits)with the ignition surface S of auxiliary propelling charge 6.

The casing of said propelling 6 may be provided with at least one safetyvalve 10 or the like.

Finally, according to still another feature of the invention, the firerseyes may be protected from the flames issuing from the nozzle or nozzles6a, by providing at the rear of said nozzle 6a a baffle 11 (shown indot-and-dash lines in FIG. 1), this baflle converging toward the rearand causing the gases issuing from the nozzle or nozzles to move towardsocket 3.

A grenade made according to the present invention is relatively shortbecause the location of the booster on the outside of the supportingsleeve does not make it necessary to overdimension said sleeve in theaxial direction.

The device does not produce an increase of the recoil, owing also to theexternal position of the booster.

The dispersion is reduced owing to the fact that the booster is locatedin the vicinity of the center of gravity of the grenade.

Finally, the vision of the firer is not impeded if the grenade isprovided with a baffle as above described.

In a general manner, while the above description discloses preferredembodiments of the invention, it should be well understood that saidinvention is not limited thereto as there might be changes made in thearrangement, disposition and form of the parts without departing fromthe present invention.

What I claim is:

1. An improved grenade which comprises, in combination,

a body,

a sleeve of revolution rigid with the rear part of said body, saidsleeve including a cylindrical rear extension adapted to fit on the endof the barrel of a launching rifle, and

an axial obstacle immovable with respect to said sleeve adapted toreceive and to transmit to said body the impact of a bullet fired fromthe launching rifle, said obstacle comprising a generally frusto-conicalpiece disposed with its small base towards the front,

an auxiliary propulsion means carried by said sleeve, including a powdercharge surrounding said sleeve coaxially thereto and close to saidobstacle, and

igniting means extending between said obstacle and said powder chargeand operative by a launching bullet striking said obstacle, saidigniting means comprising a primer located near the front of saidgenerally frusto-conical piece.

References Cited UNITED STATES PATENTS 1,376,] 19 7/1917 Sheppard 421.21,448,436 3/1923 Day 421.2 1,900,790 3/1933 Brandt 42-1.2 3,007,41011/1961 Blacker 10249.7 3,071,073 1/1963 Ammann 891.819

FOREIGN PATENTS 591,485 4/1959 Italy.

BENJAMIN A. BORCHELT, Primary Examiner I. FOX, Assistant Examiner

